Pneumatic spring with a hose rolling bellows

ABSTRACT

This invention concerns a pneumatic spring consisting of a hose roll bellows of elastomer material which is equipped, in particular, with stiffening supports. The ends of the hose roll bellows are pushed onto a connecting element and attached there by a radially ductile clamping ring particularly made out of metal. According to the invention, the connecting element and/or clamping ring are made thicker with a covering elastomer strip in the area of clamping. The elastomer strip is a component which is separate from the hose roll bellows. Several variants are presented.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a pneumatic spring comprising a hose rollbellows (pneumatic spring bellows) made of elastomer material, which inparticular is provided with stiffening supports, whereby the ends of thehose roll bellows are pushed onto a connecting element and are securedthere by means of a radially deformable clamping ring, which inparticular is made of metal (DE-A-36 43 073).

2. Description of the Related Art Including Information Disclosed Under37 C.F.R. 1.97 and 1.98.

In laid-open document DE-A-21 17 259, the pneumatic spring bellows ismade thicker at the outer ends. Conical connecting elements are expectedto make the attachment even more secure under tensile stress. Thedrawback of said design is the increased expenditure in the manufactureof such pneumatic spring bellows. A further drawback is that due to theconical clamping, the pneumatic spring bellows changes its positionunder tensile load, which means that the constructional position of thebellows is shifted as well.

Laid-open document DE-B-11 52 316 describes a pneumatic spring bellowswith core rings incorporated by vulcanization. The pneumatic springbellows is mounted here on or in conical cylinders and additionallysecured by a supporting ring and a bead. The drawback of this solutionlies in the high expenditure for the manufacture and for mounting thebellows with fastening means disposed in a pot.

A particularly critical point in pneumatic springs is the region wherethe connecting element, the hose roll bellows and the clamping ring arejoined, especially under the aspects of

influence of material variations;

influence of the manufactured diameter of the pneumatic spring bellowsin relation to the clamp-on diameter of the connecting component;

application of the pneumatic spring at different temperatures inassociation with different types of material employed for the connectingcomponent, the hose roll bellows and the clamping ring; as well as

total thickness of the hose roll bellows in relation to the stiffeningsupport, whereby the share of the elastomer is reduced or reduced evenfurther due to inherent friction.

Now, within the framework of a further development the problem is toimprove the tightness of the hose roll bellows in the region of theclamping ring.

BRIEF SUMMARY OF THE INVENTION

Said problem is solved in that the connecting component and/or theclamping ring are made thicker within the clamping region with anelastomer strip, whereby the elastomer strip is a separate structuralelement with respect to the hose roll bellows. The term “separatestructural element” means in this connection that conditioned by themanufacture, the elastomer strip is a structural element separated fromthe pneumatic spring bellows, namely as opposed to the embodimentsaccording to DE-A-21 17 259 and DE-B-11 52 316.

The following variations are usefully employed in this connection:

(A) The clamping ring has an elastomer strip applied to it byvulcanizing or gluing, said strip facing the hose roll bellows.

(B) An elastomer strip is present between the hose roll bellows and theconnecting element, said elastomer strip being installed in a groove ofthe connecting element, whereby the elastomer strip may be joined withthe connecting element by gluing.

(C) The clamping ring has an elastomer strip, which is gripping aroundthe clamping ring by means of a collar and which faces the hose rollbellows. In addition, the elastomer strip may be glued to the clampingring.

(D) The elastomer strip is designed in the form of a U-section andencloses the end of the hose roll bellows, which comprises a thickeningon both sides.

Irrespective of which of said variations is involved it is advantageousif the thickness of the elastomer strip amounts to 30% to 150%,particularly to 40% to 90% of the normal thickness of the bellows,namely based on the unstressed condition.

The invention is now explained with the help of exemplified embodimentswith reference to schematic drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a pneumatic spring according to variation A.

FIG. 2 shows a pneumatic spring according to variation B.

FIG. 3 shows a pneumatic spring according to variation C.

FIG. 4 shows a pneumatic spring according to variation D.

The following list of reference numerals applies in connection with saidfigures:

1 Connecting element with groove

2 Hose roll bellows

3 Clamping ring

4 Elastomer strip

4′ Elastomer strip

4″ Elastomer strip with collar

4′″ Elastomer strip as a U-section.

DETAILED DESCRIPTION OF THE INVENTION

According to FIG. 1, clamping ring 3 has an elastomer strip 4 applied toit by vulcanizing or gluing, said elastomer strip facing the hose rollbellows 2.

According to FIG. 2, an elastomer strip 4′ is present between the hoseroll bellows 2 and the connecting element 1, said elastomer stripsitting in a groove of the connecting element.

According to FIG. 3, clamping ring 3 has an elastomer strip 4″, whichgrips around clamping ring 3 by means of a collar and faces the hoseroll bellows 2. The advantage of this variation is that the elastomerstrip 4″, can be manufactured as a separate structural element.

According to FIG. 4, the elastomer strip 4′″ is designed as a U-sectionand encloses the end of hose roll bellows 2, which is connected with athickening on both sides.

What is claimed is:
 1. A pneumatic spring coupled in a sealedrelationship with a connecting element, the spring comprising: a) a hoseroll bellows having ends, and formed from an elastomer material whichcontains a series of stiffening supports; b) a radially deformable metalclamping ring for securing said hose roll bellows to the connectingelement; and c) substantially solid elastomer strip disposed in aclamping region of the spring between said clamping ring and theconnecting element wherein when said clamping ring is tightened, itsecures said elastomer strip, and said hose roll bellows to theconnecting element wherein said elastomer strip is a separate structuralelement from said hose roll bellows and adds a thickness to the springin said clamping region.
 2. The pneumatic spring according to claim 1,wherein said elastomer strip is attached to said clamping ring byvulcanizing or gluing wherein said elastomer strip faces said hose rollbellows.
 3. The pneumatic spring according to claim 1, wherein theconnecting element further comprises a groove and said elastomer stripis attached to the connecting element in said groove.
 4. The pneumaticspring according to claim 3, wherein said elastomer strip is attached tothe connecting element by gluing.
 5. The pneumatic spring according toclaim 1, wherein said elastomer strip is attached around said clampingring as a collar and faces said hose roll bellows.
 6. The pneumaticspring according to claim 5, wherein said elastomer strip is glued tosaid clamping ring.
 7. The pneumatic spring according to claim 1,wherein said elastomer strip is attached to said hose roll bellows andis designed as a U-section enclosing said end of said hose roll bellows.8. The pneumatic spring according to claim 1, wherein said elastomerstrip has a thickness between 30% and 150% of the normal bellowsthickness in the unstressed condition.
 9. The pneumatic spring accordingto claim 8, wherein the thickness of the elastomer strip in the regionof the clamping ring is between 40% and 90% of the normal bellowsthickness, in the unstressed condition.